Natural history of HCV infection.

Chronic hepatitis C virus (HCV) infection affects 170 million individuals worldwide. These individuals are at risk of developing both hepatological and non-hepatological manifestations. HCV is usually only fatal when it leads to cirrhosis, the final stage of liver fibrosis. Therefore, an estimate of fibrosis progression represents an important surrogate end-point for the evaluation of the vulnerability of an individual patient. In untreated patients, the median expected time to cirrhosis is 30 years; 33% of patients have an expected median time to cirrhosis of less than 20 years and 31% will only progress to cirrhosis after more than 50 years, if ever. Several factors are associated with fibrosis progression rate: duration of infection, age, male gender, consumption of alcohol, HIV co-infection and low CD4 count. Non-hepatological manifestations are frequent with more than 70% of HCV patients experiencing fatigue or at least one extrahepatic clinical manifestation involving primarily the joints, skin and muscles. Several immunological abnormalities are frequently observed, including cryoglobulins (40%),anti-nuclear antibodies (10%) and anti-smooth muscle antibodies (7%). In contrast severe extrahepatic manifestations are rare, with 1% for systemic vasculitis.